Just a quick question I've been thinking about. I installed the power windows in my '46 chevy Panel and quickly cracked the passenger side glass. It cracked right down the middle from the glass mount to the top of the glass. Now I checked them four or five times to make sure they were tracking right before putting in the glass but it still cracked. Now I put the inner door panels on and got a second crack in the same glass. OK so now I'm thinking I did something very wrong. What I did was at the top of the track I put a brace in and I'm thinking thats what caused the crack. If you look at the pic I circled where I put the brace. Now should I have done this or should this just free float? I hope you understand what I'm talking about. The pic was before final mounting.

Thanks Willys, I did the alignment with the masonite before I put in the glass and was sure I had it right. I'm thinking the brace might have pulled it out of line. Does that brace really need to be there? There was no place for it on the track I just added it thinking one should be there. The directions that came with the units were about useless so most of the time I was guessing at what I should have done.

Can't quite make out what the brace does but an ignorant opinion is yes, that is likely your problem. Those widgets usually come with all the stuff needed to make them work right. Back-seat engineering might be your problem. Still, it takes a point source of stress to crack the glass so try and find that source. Again, that is why I like the Ford motor system which retains the bullet proof factory designed window riser mechanism which will always be superior to the after-market stuff.

I have installed a few of those cable drive window regulators in cars. The problem is that, in many doors, the regulator assembly is too thick. There is not enough room for the regulator to be mounted to the inner panel, and not put excessive force on the window. Especially if you have a short glass and have it with all of the solid brackets and mounts in a horizontal line when the window is rolled up.

I have broken several window glasses in this way, so I feel qualified to help.
Is this what you have going on in your door? Sorry for the crappy drawing.

The arrows with shading are stresses

Like willys said, you need to find the stress. Take the regulator out and reinstall the glass. Measure between the mounting surface on the door and the lower window channel where the regulator bolts on to it. Compare the thickness of the regulator to your measurement. The regulator should be thinner.

You can slot the door to move the window regulator inwards towards the interior of the car. Or you can flatten some of the ribs in the panel. This gives more room for all of the parts to stack up. Don't let it float at the top..

You can try to remove some of the unnecessary mounting bracketry and reduce the overall stack thickness. Some of those mounts are fairly elaborate to allow the window to slide fore and aft while allowing no tilt. In some cars this is unnecessary.

Check your lower glass channel. Sometimes the mounting flange will allow the window glass to sit closer to the regulator, if you flip it end for end.

Get a taller window. You need to get a new piece anyway, have the glass shop cut it taller by 3 or 4 inches. This will put the stresses in less of a straight line with the hard places like the fuzzy weather strip.

Here is a drawing with some of the above fixes.

I stopped using the cable drive mechanisims. The geardrive with arm type sit lower in the door, are stronger and take up less room in a thin door. The action is smoother and less prone to tilt if you use the double arm style such as a SPW 2416U.

I don't do the junkyard. By the time I go pull a regulator out , my customer can pay for a new one.

Mike I think I know what your saying. And a pic is worth a 1000 words. I drew out what I did to show where I think I messed up. I should have said before that the glass is laminate and it only cracked the inside layer as far as myself and a couple of friends can tell. Heres the mounting bracket I made for the regulator

Now after I put the inner door panel on a second crack appeared starting at about the same point. The starting point for both cracks is where the glass mounts in the regulator. Thats why I think the brace is at fault, I'm thinking it's pulling the window inward and out of alignment.

Thanks

I also forgot to tell you that I did call the company tech line and about the only thing they could tell me was that each installation is different as to whats needed and whats not as far a bracing goes.

It's binding somewhere. I have a 39 Chevy in my shop with the same unit as yours. It came in with a broken door glass. I had a new one cut and I reinstalled it. When I went to put the door panel back on, I noticed it was cracked again in the same place. I had another one cut and I got it to work with a lot of screwing around. It's just too big for those narrow doors.
Bob

So what you are saying is that the regulator travels in a different plane than the window glass in it's run channels.

Take loose the screws that hold the window and lower window channel to the regulator. Hold the glass to prevent it from falling while you operate the window regulator. see if the window and regulator remain close to each other throughout its travel. If you find the glass is far away from the regulator at any point or way close and tight, adjust the regulator mounts to rectify it.

If your glass travels up and down nicely in its channels now, don't adjust the glass run channels to compensate or you will cause a travel bind.

First I commend Mike on his explanation and sketches. Great job. And I ALWAYS do the junk yard 'cause A) I love tearing into old stuff and making it work and, B) I am my only customer and have more time than money or sense.

bluepen - from your excellent sketch I can see that the bracket you added is 99% likely the problem. The glass channels on the edges of the glass should rule. The glass must be allowed to follow those and let the riser mechanism play second fiddle. If you free up the riser and let it float in and out as the glass rises, I am almost sure your problems will go away. That is another reason I don't like aftermarket risers. Looks like they should plop right in and work perfectly. In real life you are aligning them with the window in three dimensions inside an enclosure that gives you no room and it is a bear to do correctly. Free up the top of that riser so it can adjust itself a quarter inch or so in any direction, make sure the glass channels have snug fitting felts all the way around and you will have a winner.

Thanks for all your help folks. I'll go back now and reinvent the wheel on this window and let you know how it works out. Well as soon as I get a little time to do it, working two jobs about 100-110 hours a week at work leaves me little time to work on the truck.

Yes Willys I can see that but with the 24 hour shifts here at the Fire Dept and workin at (this is bad) Autozone on off days hours run a little short. This week was really hard on an old body, 96 at the FD and 30 at the store. very little time for much else but sleep

Thanks again
Oh and thats not complaining I do enjoy working at both of them.

I have gained more respect for you public servants. My son is half way thru the 6 month California Highway Patrol academy and boy is it tough. I guess those are the hardest jobs you learn to love. My hat goes off to you all.

Bluepen,
I have the same setup.
The center cap screw that's on the plate is an adjustment screw aswell as a pivot point. This will adjust the trueness of the plate.

Install a paint stick in the clamps, tighten the clamps and see if the paint stick is still straight. If not turn the screw either in or out until the stick is straight. Also you don't need to tighten the clamp hard to keep the glass in, just real snug. Over tightening will crack the glass also.

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